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This page gives some basic details about the Raw Refraction Render Element and how it is used in compositing.

Overview

The Raw Refraction Render Element is a color image that stores refraction information calculated from materials' refraction values in the scene. Surfaces with no refraction values set in their materials will contain no information in the render element and therefore will render as black.

In comparison, the Refraction Filter Render Element (vrayRE_Refraction_Filter) is a render element that indicates varying degrees of refraction in the scene through brightness values in the image. Multiplying these two render elements together produces the Refraction Render Element (vrayRE_Refraction) .

To properly calculate the Raw Refraction Render Element, the Refraction Render Element must also be added to the list of render elements being calculated during the rendering process to properly determine all the refraction information in the scene.

To use render elements, select from the Available render elements column and click the Add button to add the passes you wish to generate at render time. When you render the scene, the added render elements listed in the column on the right, will also render, which can be viewed from the VFB window's channel drop-down menu.

For more information on the parameters on this dialog, see the Render Elements tab page.

$V-Ray for Maya > Raw Refraction > maya2016_34003_rawRefract.png$

Attributes

The parameters for this render element appear in the Attribute Editor under Extra V-Ray Attributes.

Enabled – When checked, the render element appears in the V-Ray Virtual Frame Buffer.

Deep output – Specifies whether to include this render element in deep images.

Filename suffix – The text added to the end of the rendered file, when saved as a separate file (e.g. myrender.rawRefraction.vrimg).

Apply color mapping – Applies the color mapping options specified in the Color Management rollout of the V-Ray tab in the Render Setup window to this render element. This option is enabled by default.

Denoise – Enables the render element's denoising, provided the Denoiser render element is present.

$V-Ray for Maya > Raw Refraction > maya2020_50000_RawRefraction.jpg$

Common Uses

The Raw Refraction Render Element is useful for changing the appearance of refractive elements after rendering in a compositing or image editing application. Below are examples of possible uses.

$V-Ray for Maya > Raw Refraction > VRay_Maya_RenderElements_CommonUses_RawRefractionRE.png$
Raw Refraction Render Element

$V-Ray for Maya > Raw Refraction > VRay_Maya_RenderElements_CommonUses_Beauty.png$
Original Beauty Composite

$V-Ray for Maya > Raw Refraction > VRay_Maya_RenderElements_CommonUses_RawRefraction_ContrastRE.png$
Raw Refraction Render Element with added contrast

$V-Ray for Maya > Raw Refraction > VRay_Maya_RenderElements_CommonUses_RawRefraction_TintedContrastRE.png$
Tinted Raw Refraction Render Element with added contrast

$V-Ray for Maya > Raw Refraction > VRay_Maya_RenderElements_CommonUses_RawRefraction_Contrast_Render.png$
Refractions with more contrast

$V-Ray for Maya > Raw Refraction > VRay_Maya_RenderElements_CommonUses_RawRefraction_TintedContrast_Render.png$
Tinted Refractions with more contrast

Underlying Compositing Equation

vrayRE_Raw_Refraction x Refraction Filter = Refraction

$V-Ray for Maya > Raw Refraction > VRayRefractions_00000.png$

Notes

To properly calculate the refraction information in the Raw Refraction and Refraction Filter Render Elements, the Refraction Render Element must also be rendered at the same time, even if it's not going to be used in the compositing process. Doing so enables all the refraction information to be included in the rendering calculations.
There is initial support for Raw Refraction render element on V-Ray GPU.